<div class="refentry" lang="en" xml:lang="en"><a id="glGetColorTable"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glGetColorTable — retrieve contents of a color lookup table</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table><tr><td><code class="funcdef">void <b class="fsfunc">glGetColorTable</b>(</code></td><td>GLenum  </td><td><var class="pdparam">target</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">format</var>, </td></tr><tr><td> </td><td>GLenum  </td><td><var class="pdparam">type</var>, </td></tr><tr><td> </td><td>GLvoid *  </td><td><var class="pdparam">table</var><code>)</code>;</td></tr></table></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>target</code></em></span></dt><dd><p>
                    Must be <code class="constant">GL_COLOR_TABLE</code>,
                    <code class="constant">GL_POST_CONVOLUTION_COLOR_TABLE</code>,
                    or
                    <code class="constant">GL_POST_COLOR_MATRIX_COLOR_TABLE</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>format</code></em></span></dt><dd><p>
                    The format of the pixel data in <em class="parameter"><code>table</code></em>.
                    The possible values are
                    <code class="constant">GL_RED</code>,
                    <code class="constant">GL_GREEN</code>,
                    <code class="constant">GL_BLUE</code>,
                    <code class="constant">GL_ALPHA</code>,
                    <code class="constant">GL_LUMINANCE</code>,
                    <code class="constant">GL_LUMINANCE_ALPHA</code>,
                    <code class="constant">GL_RGB</code>,
                    <code class="constant">GL_BGR</code>,
                    <code class="constant">GL_RGBA</code>, and
                    <code class="constant">GL_BGRA</code>.
                </p></dd><dt><span class="term"><em class="parameter"><code>type</code></em></span></dt><dd><p>
                    The type of the pixel data in <em class="parameter"><code>table</code></em>.
                    Symbolic constants
                    <code class="constant">GL_UNSIGNED_BYTE</code>,
                    <code class="constant">GL_BYTE</code>,
                    <code class="constant">GL_BITMAP</code>,
                    <code class="constant">GL_UNSIGNED_SHORT</code>,
                    <code class="constant">GL_SHORT</code>,
                    <code class="constant">GL_UNSIGNED_INT</code>,
                    <code class="constant">GL_INT</code>,
                    <code class="constant">GL_FLOAT</code>,
                    <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
                    <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
                    <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
                    <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
                    <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
                    <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, and
                    <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
                    are accepted.
                </p></dd><dt><span class="term"><em class="parameter"><code>table</code></em></span></dt><dd><p>
                    Pointer to a one-dimensional array of pixel data containing the contents
                    of the color table.
                </p></dd></dl></div></div><div class="refsect1" lang="en" xml:lang="en"><a id="description"></a><h2>Description</h2><p>
            <code class="function">glGetColorTable</code> returns in <em class="parameter"><code>table</code></em> the contents of the color table specified
            by <em class="parameter"><code>target</code></em>. No pixel transfer operations are performed, but pixel
            storage modes that are applicable to
            <a class="citerefentry" href="glReadPixels"><span class="citerefentry"><span class="refentrytitle">glReadPixels</span></span></a> are performed.
        </p><p>
            If a non-zero named buffer object is bound to the <code class="constant">GL_PIXEL_PACK_BUFFER</code> target
            (see <a class="citerefentry" href="glBindBuffer"><span class="citerefentry"><span class="refentrytitle">glBindBuffer</span></span></a>) while a histogram table is
            requested, <em class="parameter"><code>table</code></em> is treated as a byte offset into the buffer object's data store.
        </p><p>
            Color components that are requested in
            the specified <em class="parameter"><code>format</code></em>, but which are not included in the internal
            format of the color lookup table, are returned as zero.  The
            assignments of internal color components to the components
            requested by <em class="parameter"><code>format</code></em> are
        </p><div class="informaltable"><table><colgroup><col /><col /></colgroup><thead><tr><th><span class="bold"><strong>
                        Internal Component
                        </strong></span></th><th><span class="bold"><strong>
                        Resulting Component
                        </strong></span></th></tr></thead><tbody><tr><td>
                        Red
                        </td><td>
                        Red
                        </td></tr><tr><td>
                        Green
                        </td><td>
                        Green
                        </td></tr><tr><td>
                        Blue
                        </td><td>
                        Blue
                        </td></tr><tr><td>
                        Alpha
                        </td><td>
                        Alpha
                        </td></tr><tr><td>
                        Luminance
                        </td><td>
                        Red
                        </td></tr><tr><td>
                        Intensity
                        </td><td>
                        Red
                        </td></tr></tbody></table></div><p>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="notes"></a><h2>Notes</h2><p>
            <code class="function">glGetColorTable</code> is present only if <code class="code">ARB_imaging</code> is returned when <a class="citerefentry" href="glGetString"><span class="citerefentry"><span class="refentrytitle">glGetString</span></span></a>
            is called with an argument of <code class="constant">GL_EXTENSIONS</code>.
        </p><p>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="errors"></a><h2>Errors</h2><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>target</code></em> is not one of the allowable
            values.
        </p><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>format</code></em> is not one of the allowable
            values.
        </p><p>
            <code class="constant">GL_INVALID_ENUM</code> is generated if <em class="parameter"><code>type</code></em> is not one of the allowable
            values.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>type</code></em> is one of
            <code class="constant">GL_UNSIGNED_BYTE_3_3_2</code>,
            <code class="constant">GL_UNSIGNED_BYTE_2_3_3_REV</code>,
            <code class="constant">GL_UNSIGNED_SHORT_5_6_5</code>, or
            <code class="constant">GL_UNSIGNED_SHORT_5_6_5_REV</code>
            and <em class="parameter"><code>format</code></em> is not <code class="constant">GL_RGB</code>.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>type</code></em> is one of
            <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4</code>,
            <code class="constant">GL_UNSIGNED_SHORT_4_4_4_4_REV</code>,
            <code class="constant">GL_UNSIGNED_SHORT_5_5_5_1</code>,
            <code class="constant">GL_UNSIGNED_SHORT_1_5_5_5_REV</code>,
            <code class="constant">GL_UNSIGNED_INT_8_8_8_8</code>,
            <code class="constant">GL_UNSIGNED_INT_8_8_8_8_REV</code>,
            <code class="constant">GL_UNSIGNED_INT_10_10_10_2</code>, or
            <code class="constant">GL_UNSIGNED_INT_2_10_10_10_REV</code>
            and <em class="parameter"><code>format</code></em> is neither <code class="constant">GL_RGBA</code> nor <code class="constant">GL_BGRA</code>.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
            <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and the buffer object's data store is currently mapped.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
            <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and the data would be packed to the buffer
            object such that the memory writes required would exceed the data store size.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if a non-zero buffer object name is bound to the
            <code class="constant">GL_PIXEL_PACK_BUFFER</code> target and <em class="parameter"><code>table</code></em> is not evenly divisible
            into the number of bytes needed to store in memory a datum indicated by <em class="parameter"><code>type</code></em>.
        </p><p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <code class="function">glGetColorTable</code> is executed
            between the execution of <a class="citerefentry" href="glBegin"><span class="citerefentry"><span class="refentrytitle">glBegin</span></span></a> and the corresponding
            execution of <a class="citerefentry" href="glEnd"><span class="citerefentry"><span class="refentrytitle">glEnd</span></span></a>.
        </p></div><div class="refsect1" lang="en" xml:lang="en"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
            <a class="citerefentry" href="glGetColorTableParameter"><span class="citerefentry"><span class="refentrytitle">glGetColorTableParameter</span></span></a>
        </p><p>
            <a class="citerefentry" href="glGet"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a> with argument <code class="constant">GL_PIXEL_PACK_BUFFER_BINDING</code>
        </p></div>
        {$pipelinestall}{$examples}
        <div class="refsect1" lang="en" xml:lang="en"><a id="seealso"></a><h2>See Also</h2><p>
            <a class="citerefentry" href="glColorTable"><span class="citerefentry"><span class="refentrytitle">glColorTable</span></span></a>,
            <a class="citerefentry" href="glColorTableParameter"><span class="citerefentry"><span class="refentrytitle">glColorTableParameter</span></span></a>
        </p></div><div class="refsect1" lang="en" xml:lang="en"><div id="Copyright"><h2>Copyright</h2><p>
            Copyright © 1991-2006
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/" target="_top">https://web.archive.org/web/20171022161616/http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></div>
